1. Field of the Invention
Exemplary embodiments of the present invention relate to a jitter tolerance test.
2. Discussion of the Background
The input jitter of a clock and data recovery (CDR) can be modeled as the sum of the accumulated and non-accumulative jitter. The non-accumulative period jitter does not accumulate over time and has bounded variance in general. Data-dependent deterministic jitter is a subset of the non-accumulative jitter. The accumulated jitter, on the contrary, is unbounded in nature and increases indefinitely with time.
A jitter tolerance mask provides the information on the accumulated and random non-accumulative jitter of a serial link.
Even if the practical jitter in a link is hardly composed of sinusoids, the jitter tolerance specification is defined with sinusoids for testing purpose. In practice, the jitter in serial links carrying real traffic is more like random noise.